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/* -----------------------------------------------------------------------------
Copyright (c) 2006 Simon Brown si@sjbrown.co.uk
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-------------------------------------------------------------------------- */
#include <squish.h>
#include "colourset.h"
#include "maths.h"
#include "rangefit.h"
#include "clusterfit.h"
#include "colourblock.h"
#include "alpha.h"
#include "singlecolourfit.h"
namespace squish {
static int FixFlags( int flags )
{
// grab the flag bits
int method = flags & ( kDxt1 | kDxt3 | kDxt5 );
int fit = flags & ( kColourIterativeClusterFit | kColourClusterFit | kColourRangeFit );
int metric = flags & ( kColourMetricPerceptual | kColourMetricUniform );
int extra = flags & kWeightColourByAlpha;
// set defaults
if( method != kDxt3 && method != kDxt5 )
method = kDxt1;
if( fit != kColourRangeFit )
fit = kColourClusterFit;
if( metric != kColourMetricUniform )
metric = kColourMetricPerceptual;
// done
return method | fit | metric | extra;
}
void Compress( u8 const* rgba, void* block, int flags )
{
// compress with full mask
CompressMasked( rgba, 0xffff, block, flags );
}
void CompressMasked( u8 const* rgba, int mask, void* block, int flags )
{
// fix any bad flags
flags = FixFlags( flags );
// get the block locations
void* colourBlock = block;
void* alphaBock = block;
if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
colourBlock = reinterpret_cast< u8* >( block ) + 8;
// create the minimal point set
ColourSet colours( rgba, mask, flags );
// check the compression type and compress colour
if( colours.GetCount() == 1 )
{
// always do a single colour fit
SingleColourFit fit( &colours, flags );
fit.Compress( colourBlock );
}
else if( ( flags & kColourRangeFit ) != 0 || colours.GetCount() == 0 )
{
// do a range fit
RangeFit fit( &colours, flags );
fit.Compress( colourBlock );
}
else
{
// default to a cluster fit (could be iterative or not)
ClusterFit fit( &colours, flags );
fit.Compress( colourBlock );
}
// compress alpha separately if necessary
if( ( flags & kDxt3 ) != 0 )
CompressAlphaDxt3( rgba, mask, alphaBock );
else if( ( flags & kDxt5 ) != 0 )
CompressAlphaDxt5( rgba, mask, alphaBock );
}
void Decompress( u8* rgba, void const* block, int flags )
{
// fix any bad flags
flags = FixFlags( flags );
// get the block locations
void const* colourBlock = block;
void const* alphaBock = block;
if( ( flags & ( kDxt3 | kDxt5 ) ) != 0 )
colourBlock = reinterpret_cast< u8 const* >( block ) + 8;
// decompress colour
DecompressColour( rgba, colourBlock, ( flags & kDxt1 ) != 0 );
// decompress alpha separately if necessary
if( ( flags & kDxt3 ) != 0 )
DecompressAlphaDxt3( rgba, alphaBock );
else if( ( flags & kDxt5 ) != 0 )
DecompressAlphaDxt5( rgba, alphaBock );
}
int GetStorageRequirements( int width, int height, int flags )
{
// fix any bad flags
flags = FixFlags( flags );
// compute the storage requirements
int blockcount = ( ( width + 3 )/4 ) * ( ( height + 3 )/4 );
int blocksize = ( ( flags & kDxt1 ) != 0 ) ? 8 : 16;
return blockcount*blocksize;
}
void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags )
{
// fix any bad flags
flags = FixFlags( flags );
// initialise the block output
u8* targetBlock = reinterpret_cast< u8* >( blocks );
int bytesPerBlock = ( ( flags & kDxt1 ) != 0 ) ? 8 : 16;
// loop over blocks
for( int y = 0; y < height; y += 4 )
{
for( int x = 0; x < width; x += 4 )
{
// build the 4x4 block of pixels
u8 sourceRgba[16*4];
u8* targetPixel = sourceRgba;
int mask = 0;
for( int py = 0; py < 4; ++py )
{
for( int px = 0; px < 4; ++px )
{
// get the source pixel in the image
int sx = x + px;
int sy = y + py;
// enable if we're in the image
if( sx < width && sy < height )
{
// copy the rgba value
u8 const* sourcePixel = rgba + 4*( width*sy + sx );
for( int i = 0; i < 4; ++i )
*targetPixel++ = *sourcePixel++;
// enable this pixel
mask |= ( 1 << ( 4*py + px ) );
}
else
{
// skip this pixel as its outside the image
targetPixel += 4;
}
}
}
// compress it into the output
CompressMasked( sourceRgba, mask, targetBlock, flags );
// advance
targetBlock += bytesPerBlock;
}
}
}
void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags )
{
// fix any bad flags
flags = FixFlags( flags );
// initialise the block input
u8 const* sourceBlock = reinterpret_cast< u8 const* >( blocks );
int bytesPerBlock = ( ( flags & kDxt1 ) != 0 ) ? 8 : 16;
// loop over blocks
for( int y = 0; y < height; y += 4 )
{
for( int x = 0; x < width; x += 4 )
{
// decompress the block
u8 targetRgba[4*16];
Decompress( targetRgba, sourceBlock, flags );
// write the decompressed pixels to the correct image locations
u8 const* sourcePixel = targetRgba;
for( int py = 0; py < 4; ++py )
{
for( int px = 0; px < 4; ++px )
{
// get the target location
int sx = x + px;
int sy = y + py;
if( sx < width && sy < height )
{
u8* targetPixel = rgba + 4*( width*sy + sx );
// copy the rgba value
for( int i = 0; i < 4; ++i )
*targetPixel++ = *sourcePixel++;
}
else
{
// skip this pixel as its outside the image
sourcePixel += 4;
}
}
}
// advance
sourceBlock += bytesPerBlock;
}
}
}
} // namespace squish
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